Integrated circuits or ICs, as they are sometimes called, are assembled into a variety of package types. Some of the more common include dual in-line packages (DIPs), quad-packs, plastic leaded chip carriers (PLCCs) and pin grid arrays (PGAs). Typically, all of these packages are stored and transported in some form of tube, rod or rail magazine. The tubes are, for example, approximately 50 cm long, and are made of transparent, antistatic synthetic material, such as a resilient plastic. The interior cross-section of the tube is usually somewhat adapted to the cross-section of the package that is to contain. For example, when DIPs are stored, the tube has a chamber with a substantially U-shaped profile, see, for example, FIG. 1. The IC packages lie in tandem between the concave wall that is protruding inward toward the center of the tube and the wall of the tube opposite the protrusion. The connecting legs or leads of the DIPs project into those areas of the chamber which form the sides of the U-shaped profile of the chamber.
It is conventional to use rubber stoppers or sealing pins extending transversely through the tube chamber to seal the rods or magazines. If one or several packages are to be taken out of the tube, the rubber stopper or the sealing pin must be removed at one end of the tube and the tube must then be tilted so that the desired number of ICs slide out. The open end of the rod-magazine is then kept shut with one finger and the rubber stopper or sealing pin is inserted again. This method is particularly troublesome and difficult if the rod or tube is, for example, to be placed upon a device handler or tester or a printed circuit board assembly apparatus that will use the packages on an assembly table for putting together printed circuit boards. In these cases, the tube must then be kept closed with a finger until immediately before insertion into the handler. Shortly before insertion, however, the finger performing the closing action must then be taken away from the opening due to lack of space, and as a result, there is a danger that the IC packages will unintentionally slide out of the tube prematurely.
Generally, these conventional tubes or rails have a cross-section or profile that prevents the components from rotating in the tube, but at the same time permitting them to slide longitudinally for feeding into the device handlers. It can be appreciated that devices with similar cross sections, that would fit in a particular type of shipping tube or rail, may be of different lengths. And since the tubes are of a standard size and have approximately the same lengths, when the devices are loaded into the standard sized tubes, there can be considerable distance between the parts, and between the parts and the end securing means. This is particularly true when the tube does not contain the maximum number of that size of part.
It will further be appreciated that during the handling and shipping of tubes or rails containing the IC parts that the parts will knock against each other. Such knocking or sharp contacts between the parts due to the motions of shipping and handling will occasionally cause the bodies of the packages to chip or crack, sometimes damaging the device so much that it cannot be used. This problem is particularly acute with ceramic packages, since the ceramic package bodies are considerably more brittle than the plastic bodiess. Further, both the ceramic bodies and the integrated circuits inside are more expensive than their plastic counterparts, thus, the problem of package knocking can be costly.
A number of schemes have been devised to modify both the packages and the tubes to address this problem. For example, various bumber structure have been added to the ends of the packages that contact each other. Alternatively, the rails have been modified to more securely hold the package. These solutions tend to make the packages or the tubes or both more expensive. Further, the industry has widely accepted the conventional tubes or rails, and considerable equipment is presently being used that accepts the conventional rails. Thus, for a new rail or tube design to be accepted by the industry, it must be compatible with the existing handling equipment.